The finishing for corrugated paper, chipboard and other papers useful for packaging usually includes punching and cutting to provide paper blanks which then may be further assembled as cardboard boxes, various packaging boxes and the like. Two general types of die cutters for such punching and cutting processes are known. The first type is platen-type die cutters. The second type is rotary die cutters.
Platen die cutters have frequently been utilized rather than rotary die cutters because of superior accuracy. This accuracy is obtained at the expense of productivity because of the reciprocating stop and start activity of the blank and platen. Rotary die cutting has been limited in its accuracy, primarily due to uneven wear of the anvils and due to the tendency of the anvils to develop harmonic vibrations during use thereof.
Attempts to improve the quality of die cuts from rotary die cutting have been made for several years by attempting to adapt steel-to-steel die cutting methods to rotary machines. These attempts have largely not been accepted in this country because of the extreme accuracy required of the die boards. Such accuracy has meant that the die board manufacturing costs are quite high.
One attempt to provide steel-to-steel die cutting is disclosed by U.S. Pat. No. 3,823,633. An anvil roller thereof is cushioned by having a plurality of roller sleeve segments inserted beneath respective steel sleeve segments. However, a cutting roller for combination with this anvil roller requires various specialized die board arrangements, and is not adaptable to conventionally constructed die boards.
Accordingly, it is an object of the present invention to provide an improved anvil suitable for cooperation with a rotatable die cylinder having conventional die boards thereupon.
It is a further object of the present invention that use of the anvil thereof provides more accurate blanks therefrom. Such improved accuracy of blanks is particularly desirable, as the trend in the corrugated industry is towards the increasing use of automatic finishing and assembling stages.